Snap-action switching apparatus

ABSTRACT

A snap-action switching apparatus comprised of two external yokes at opposite positions separated by a certain distance in which one center yoke is inserted, a closed magnetic path for which one of the said external yokes is selectively used by alternately attracting the center yoke onto said two external yokes, and at least one galvano-magnetro effect device which is provided on at least one of said three yokes so that the galvanomagnetro effect device functions when the central yoke and external yokes form a closed magnetic path.

United States Patent Mogi Nov. 21, 1972 [54] SNAP-ACTION SWITCHING 3,344,850 lO/ I967 De Forest ..324/45 X APPARATUS Primary Examiner-C. L. Albritton [72] Inventor' Toshlo Mogl Ayasemachl Japan Attorney.lames E. Armstrong and Ronald S. Cornell [73] Assignee: Denki Onkyo C0,, Ltd. 221 Filed: Oct. 14,1970 [57] ABSTRACT [21] Appl. No.: 80,602 A snap-action switching apparatus comprised of two external yokes at opposite positions separated by a certain distance inrwhich one center yoke is inserted, Foreign Application ity Data a closed magnetic path for which one of the said ex- Oct. 18, 1969 Japan ..44/99229 temal Yokes is Selectively used by alternately attracting the center yoke onto said two external yokes, and [52] US. Cl. ..338/32 R, 335/1, 335/207 at least one salvano-magnetro effect device which is [51] Int. Cl. ..H0lc 7/16 Provided on at least one of said three yokes so that the [58] Field of Search ..338/32 R, 32 H; 323/94 H; galvano-magnetro effect device functions n the 324/45, 46; 317/235 H; 335/1, 207; 307/309 central yoke and external yokes form a closed magnetic path. [56] References Cited 8 Claims, 6 Drawing Figures PATENTED nuv21 m2 SHEET 1 [IF 2 1 SNAP-ACTION SWITCHING APPARATUS BACKGROUND OF THE INVENTION wear and fatigue of the spring mechanism which is required in addition to the main mechanism.

The present invention is intended to provide a snapaction switchingapparatus which is free from such deficiency as mentioned above.

SUMMARY The present invention provides a snap-action switching apparatuscomprised of an external frame on which two magnetic yokes are positioned with a certain space so that both ends of the magnetic yokes are opposed to each other, a magnetic center yoke which is inserted in said space so that. both ends of the center yoke are opposite to both ends of theyokes at the external frame, a bearing means such as, for example, a shaft and support frame which holds the external frame or the center yoke, which can be kept movable, so that the center yoke contacts one of theyokes of the external frame selectively and alternately, at least one galvano-magnetro effect device being provided on at least one of thecenter yoke and two yokes of the external frame, and an external load circuit and external input circuit being connected to the galvano-magnetro effect device, wherein at least one of a pair of yokes of the external frame and the center yoke is made of a magnet, the center yoke is attracted to the yokes of the external frame to which the center yoke contacts which it is alternately made to contact two yokes of the external frame and forms a closed magnetic path, and the galvano-rnagnetro effect device is arranged to vary the density of the magnetic flux applied to the galvanomagnetro effect device through alternate contact of the center yoke with a pair of yokes of the external frame.

BRIEFDESCRIPTION OF THE DRAWINGS The present invention is illustratedin the accompanying drawings whereof:

FIG. 1 is an isometric view of the snap-action switching apparatus according to the present invention;

FIG. 2 is a side view of said apparatus;

FIG. 3 is a side view of an embodiment of said apparatus, and FIGS. 4, 5 and 6 are isometric views of other embodiments of the present invention.

DETAILED DESCRIPTION Referring to FIGS. 1 to 2 of the drawings, there is shown a snap-action switching apparatus comprised of an external frame 10 to which two U-shaped magnetic yokes 11 and 11' are fixed with two non-magnetic frame plates 12 and 12, a magnetic center yoke which performs switching by using the inside frame plate of said external frame as a bearing means and galvano-magnetro effect devices 30 and 30 such as, for example, a Hall effect device or a magneto-resistance device which are provided respectively at yokes 11 and 11' of the external frame.

Outer frame plate 12 of external frame 10 is fixed to a base which is not shown. Both ends 11a and 11a of magnetic yokes l1 and 11' are fixed at the rear side of both extended faces 12a and 12a of inside frame plate 12, the-cross section of which is L-shaped; accordingly, an L-shaped space 13 which is open at one side is formed between yokes 11 and 11.

Center yoke 20 is made of a bar magnet with a square section and magnetic poles N and S at its both ends and is inserted into space 13 while comer'2l of one side is forced to contact corner 12b of inside frame .plate 12.

Center yoke 20 is' designed so that angle 0 of corner 21, which is a fulcrum for movement of the center yoke, is less than opening angle 6 of corner 12b which is a bearing point of inside frame plate 12. Accordingly, when surface 22 of the center yoke is attracted to end surface 11a of one yoke 11-of the external frame, the other surface 22 of the center yoke separates from the other yoke 11' of the external frame. To actuate the center yoke, lever portion'23 for operation is provided outside center yoke 20.

A galvano-magnetro effect device 30 is inserted in gap 11b formed at the intermediate portion of said yoke 11 and the other galvano-magnetro effect device 30.is inserted between end 11a of said yokell and extended surfacel2a of frame plate 12. Both galvanomagnetro effect devices 30 and 30' are connected to an external power supply and load circuits which are not shown and are devised so that the load circuits are actuated with variation of the output of said galvano-magnetro effect devices.

The snap-action switching apparatus according to the present invention is as described above. When center yoke 20 contacts upper yoke 11 of external frame 10, as shown in FIG. 2, center yoke 20 is attracted to yoke 11 and a closed magnetic path includv ing yoke 11 is formed.

Therefore, the density of the magnetic flux flowing in yoke 11 increases and the magnetic flux concentrates on galvano-magnetro effect device 30, thus enabling it to actuate the load circuits connected to this device.

When operation lever 23 of center yoke 20 is pushed down, center yoke 20 is separated from upper yoke 11 of the external frame and is attracted to lower yoke l l as shown with a broken line in FIG. 2. Then the closed magnetic path including lower yoke 11' is formed and the magnetic path is concentrated on galvano-magnetro effect device 30 of yoke 11 Since the load circuits connected to galvano-magnetro effect device 30' of lower yoke 11' operate under the condition mentioned above while the magnetic path including upper yoke 11 is opened, the magnetic flux being supplied to galvano-magnetro effect device 30 of upper yoke 11 is interrupted and the load circuit connected to said device 30 are prevented from operatmg.

Thus, this snap-action switching apparatus performs snap-action type switching with alternate attraction of center yoke 20 to yokes l1 and 11' of external frame 10. For this reason, it does not require an independent spring mechanism; accordingly, the apparatus is advantageous in the point that it can be designed to be compact, the cost of production can be reduced and accurate switching snap-action can be maintained for a long period.

In said embodiment, the shape of said center yoke cannot always be a quadrilateral and wear of the portion at angle 21 can be reduced by curving the surface with angle 21, as illustrated in FIG. 3. Further, rotation stroke d of center yoke can easilybe increased.

FIGS. 4 to, 6 illustrate snap-action switching apparatus according to the present invention. The apparatus of the embodiment shown in FIG. 4 is comprised of yokes l1 and 11' of external frame 10 which are made of magnets and are arranged in parallel, center yoke 20 which is made of elastic plate material and is provided in space 13 between the yokes of external frame 10 and operation lever 23 which is provided at said center yoke 20 and is rotated around pivot 40 of a bearing means as the fulcrum. This embodiment is advantageous in the point that center yoke 20 can contact yokes 11 and 11' of the external frame due to its elasticity since center yoke 20 can be selectively pressed onto yokes l1 and 11 of the external frame while being bent and that the apparatus can be compact because center yoke 20 can be made thin.

The apparatus of the embodiment shown in FIG. 5 is comprised of two U-shaped yokes 11 and 11 made of magnets at opposite positions and strip-shaped center yoke 20 which is provided in space 13 between yokes 11 and 11 and is rotatably fixed by pivot 40 at its end. This embodiment is advantageous in the point that the free end of center yoke 20 can be operation lever 23 and stroke d of center yoke 20 can be freely determined. l r

The apparatus of the embodiment shown in FIG. 6 is comprised of center yoke 20, which is fixed at base 50, and yokes 11 and 11' of the external frame which are forced to alternately contact center yoke 20 by rotating external frame 10 around pivot 40 as the fulcrum.

As known from the embodiment shown in FIG. 6, the apparatus is advantageous in the point that galvanomagnetro effect devices and 30' can be respectively arranged at the end faces of projections 24 and 24' of center yoke 20, which are extended to be T-shaped toward yokes 11 and 11 of the external frame, because the magnetic flux does not flow in projection 24' when projection 24 is attracted to yoke 11.

The number of galvano-magnetro effect devices 30 can be varied widely; for example, galvano-magnetro effect device 30 can be arranged in only the closed magnetic path which is formed with yoke 11 of the external frame. In this case, even though center yoke 20 is attracted to yoke 11, no galvano-magnetro effect device exists in this closed magnetic path and, accordingly, the entire apparatus incorporates only one galvano-magnetro effect device which operates normally.

As shown in FIG. 3, both center yoke 20 and the pair of yokes 11 and 11' of the external frame can be made of magnets whereby the magnetic force can be greater.

What is claimed is: a

l. A snap-action switching apparatus comprising:

a. an external frame,

b. two magnetic outer yokes attached to said external frame each having a pair of ends, the pair of ends I of one of said magnetic outer yokes being positioned substantially opposite to but spaced from the pair of ends of the other of said magnetic outer yokes, r c. a magnetic center yoke disposed in the space between said two magnetic outer yokes having ends positioned to oppose both ends of each of said magnetic outer yokes, .said magnetic center yoke being movable relative to said two magnetic outer yokes such that said magnetic center yoke is adapted to selectively and alternately contact first both ends of one of said magnetic outer yokes and then both ends of the other of said magnetic outer yokes, a

at least one galvano-magnetro effect device provided on at least one of said yokes, at least one end pair of said two magnetic outer yokes, both ends of at least one of said magnetic outer yoke or the magnetic center yoke being made of a magnet so that said magnetic center yoke may be magnetically attracted to both ends of at least one of said magnetic outer yokes to form a closed magnetic path, said galvano-magnetro effect device positioned such that the density of the magnetic flux applied thereto is forced to vary with alternate contact of said magnetic center yoke with said magnetic outer yokes.

2. A snap-action switching apparatus according to claim 1 wherein said magnetic center yoke is pivotally disposed between said two magnetic outer yokes and is adapted to rotate into contact with said magnetic outer yokes.

3. A snap-action switching apparatus, according to claim 2, wherein said external frame is fixed on the extended surfaces of a frame plate with an L-shaped section to form an L-shaped space which is open at one side; the center yoke, one side of which is angle-cornered, being inserted in said space in contact with a corner of the frame plate; and the angle of the corner of the center yoke being smaller than the angle of the corner of the frame plate so that two surfaces in reference to the corner of the center yoke alternately contacts with and separates from the yokes of the external frame along with rotation of the center yoke in reference to the corner of the center yoke born by the corner of the frame plate.

4. A snap-action switching apparatus, according to claim 3, wherein a corner formed at one side of the center yoke which is a fulcrum of rotation of the center yoke is curved.

5. A snap-action switching apparatus, according to claim 2, wherein the center yoke is made of elastic material having a strip shape, said center yoke being supported by a pivot so that it can rotate in the space formed between two yokes of the external frame.

6. A snap-action switching apparatus, according to claim 2, wherein the center yoke is strip-shaped and one end thereof is pivotally mounted so that the center yoke can rotate in the space formed between two external yokes.

7. A snap-action switching apparatus, according to claim 1, wherein both ends of the center yoke are ex-' tended toward the yokes of the external frame so as t be T-shaped.

8. A snap-action switching apparatus, according to claim 7, wherein the end faces of the T-shaped projected portions are provided with at least one galvanomagnetro effect device. 

1. A snap-action switching apparatus comprising: a. an external frame, b. two magnetic outer yokes attached to said external frame each having a pair of ends, the pair of ends of one of said magnetic outer yokes being positioned substantially opposite to but spaced from the pair of ends of the other of said magnetic outer yokes, c. a magnetic center yoke disposed in the space between said two magnetic outer yokes having ends positioned to oppose both ends of each of said magnetic outer yokes, said magnetic center yoke being movable relative to said two magnetic outer yokes such that said magnetic center yoke is adapted to selectively and alternately contact first both ends of one of said magnetic outer yokes and then both ends of the other of said magnetic outer yokes, d. at least one galvano-magnetro effect device provided on at least one of said yokes, at least one end pair of said two magnetic outer yokes, both ends of at least one of said magnetic outer yoke or thE magnetic center yoke being made of a magnet so that said magnetic center yoke may be magnetically attracted to both ends of at least one of said magnetic outer yokes to form a closed magnetic path, said galvano-magnetro effect device positioned such that the density of the magnetic flux applied thereto is forced to vary with alternate contact of said magnetic center yoke with said magnetic outer yokes.
 1. A snap-action switching apparatus comprising: a. an external frame, b. two magnetic outer yokes attached to said external frame each having a pair of ends, the pair of ends of one of said magnetic outer yokes being positioned substantially opposite to but spaced from the pair of ends of the other of said magnetic outer yokes, c. a magnetic center yoke disposed in the space between said two magnetic outer yokes having ends positioned to oppose both ends of each of said magnetic outer yokes, said magnetic center yoke being movable relative to said two magnetic outer yokes such that said magnetic center yoke is adapted to selectively and alternately contact first both ends of one of said magnetic outer yokes and then both ends of the other of said magnetic outer yokes, d. at least one galvano-magnetro effect device provided on at least one of said yokes, at least one end pair of said two magnetic outer yokes, both ends of at least one of said magnetic outer yoke or thE magnetic center yoke being made of a magnet so that said magnetic center yoke may be magnetically attracted to both ends of at least one of said magnetic outer yokes to form a closed magnetic path, said galvano-magnetro effect device positioned such that the density of the magnetic flux applied thereto is forced to vary with alternate contact of said magnetic center yoke with said magnetic outer yokes.
 2. A snap-action switching apparatus according to claim 1 wherein said magnetic center yoke is pivotally disposed between said two magnetic outer yokes and is adapted to rotate into contact with said magnetic outer yokes.
 3. A snap-action switching apparatus, according to claim 2, wherein said external frame is fixed on the extended surfaces of a frame plate with an L-shaped section to form an L-shaped space which is open at one side; the center yoke, one side of which is angle-cornered, being inserted in said space in contact with a corner of the frame plate; and the angle of the corner of the center yoke being smaller than the angle of the corner of the frame plate so that two surfaces in reference to the corner of the center yoke alternately contacts with and separates from the yokes of the external frame along with rotation of the center yoke in reference to the corner of the center yoke born by the corner of the frame plate.
 4. A snap-action switching apparatus, according to claim 3, wherein a corner formed at one side of the center yoke which is a fulcrum of rotation of the center yoke is curved.
 5. A snap-action switching apparatus, according to claim 2, wherein the center yoke is made of elastic material having a strip shape, said center yoke being supported by a pivot so that it can rotate in the space formed between two yokes of the external frame.
 6. A snap-action switching apparatus, according to claim 2, wherein the center yoke is strip-shaped and one end thereof is pivotally mounted so that the center yoke can rotate in the space formed between two external yokes.
 7. A snap-action switching apparatus, according to claim 1, wherein both ends of the center yoke are extended toward the yokes of the external frame so as to be T-shaped. 